For example, an Li ion battery is known as a high-voltage and high-energy density battery. The Li ion battery is a cation-based battery utilizing a reaction between an Li ion and a cathode active material and a reaction between an Li ion and an anode active material. On the other hand, a fluoride ion battery utilizing a reaction of a fluoride ion is known as an anion-based battery. For example, in Patent Literature 1, a fluoride ion battery provided with an electrolyte containing an anode, a cathode and a fluoride salt, and a predetermined additive is disclosed.
In Patent Literature 1, it is described that an ionic liquid is used as a solvent of a liquid electrolyte, and 1-methyl,1-propylpiperidinium(MPP)cation, butyltrimethylammonium(BTMA)cation and 1-butyl,1-methylpyrrolidinium(BMP)cation are described as a cation of the ionic liquid. Incidentally, any of these cations does not correspond to an aromatic cation.